Method of burning brick.



J. Q. BENNETT. METHOD OF BURNING BRICK.

APPLICATION FILED 00114.,1909.

988,299, Patented Apr.4, 1911.

2 BHEETS-BHBET 1.

1m: NORRIS PETERS co. WASHINGTON, m c.

J. Q. BENNETT. METHOD OF BURNING'BRICK.

1 1110111011 FILED 001.14, 1909.

988,299. Patented Apr. 4, 1911.

2 SHEETS-8321GT 2.

ms NORRIS PETERS cm, wasmmzrou, n. c.

TINTTED STATES PATENT @FETEE.

JOSIAH Q. BENNETT, 0F CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO BOSTON BRICK COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

METHOD OF BURNING BRICK.

To all whom it may concern:

Be it known that I, JosIAH Q. BENNETT, a citizen of the United States, residing at Cambridge, county of Middlesex, and State of Massachusetts, have invented an Improvement in Methods of Burning Brick, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to a process of burning brick by which coal can be Successfully used as a fuel.

It has heretofore been the common practice to use wood in burning brick, partly because the wood fire can be so handled as to distribute the heat evenly throughout the kiln and thus secure an even burning of the brick, and partly because the use of wood as a fuel gives the burned brick the desired dark red color. Owing to the increasing scarcity of wood and the corresponding increase in its price, it is extremely desirable to be able to substitute some cheaper fuel for wood, and with this object in view various attempts have been made to use coal as fuel. One objection to the use of coal has been that it produces a strong local heat which is apt to injure the brick in the immediate vicinity of the fire, but which can not be readily distributed throughout the kiln to effect the proper burning of the bricks at a distance from the fire; another objection has been that the use of coal is apt to produce whitewashed bricks, as it is termed, that is, discolored or light bricks.

After many experiments with coal as fuel for burning bricks, I have discovered a process of using coal by which bricks can be produced that are equally as good, if not better, than those produced by burning with wood, and by means of which a kiln can be burned with less percentage of waste than is usually found in a wood-burned kiln.

I will first describe one embodiment of my invention and then point out the novel features thereof in the appended claims.

Referring to the drawings Figure 1 is a vertical section of a kiln extending from one head to the other and showing one step in my improved method, said section being taken on the line yy, Fig. 2; Fig. 2 is a partial section on the line w-w, Fig. 1; Fig. 3 is a horizontal section through the arches;

Specification of Letters Patent.

Application filed October 14, 1909.

Patented Apr. 4, 1911. Serial N 0. 522,530.

Fig. 4 is a detail showing the top of the corner of the kiln.

In burning a kiln of brick, the first part of the burning process is called clearing the kiln, a term which is used to describe the operation of drying the green brick and driving ofi the water smoke therefrom; the latter part of the burning process is called settling the kiln, and it is during this part of the process that the bricks are burned hard and are given their desired dark red color. The term settling the kiln has been adopted to describe this operation because the bricks shrink somewhat during the latter part of the burning operation, and as a result the top of the kiln gradually settles. Those who are in the habit of burning brick are accustomed to determine when the burning of the kiln is completed by observing the settling of the kiln, and in a perfectly burned kiln, the settling of the kiln is substantially uniform all over the top. In previous experiments with the use of coal as fuel for burning brick with which I have been concerned, the kiln has been burned by using coal at the ends of the arches and wood in the center of the arches and by burning the coal under a forced draft. While these experiments gave fairly good results, yet it was found that the kiln was very apt to settle to a greater extent in the center than at the heads, and although the bricks in the center of the kiln were of the proper hardness and color, yet those composing the heads of the kiln were not always burned sufficiently hard and were apt to be of too light a color to command the best prices in the market. The reason for this failure to properly burn the heads seemed to be that with former methods of using coal, it had not been possible to throw the heat clear into the heads of the kiln. I have discovered that if the coal is burned under a forced draft during the first part of the process or while the kiln is clearing, and if after the kiln has cleared and while the kiln is settling, the forced draft is materially reduced and at the same time the kiln is fired from the opposite ends alternately, it is possible to throw the heat into the heads in such a way that the kiln will settle uniformly and as good bricks will be produced in the heads as are produced in the body of the kiln.

In carrying out my improved process, I

construct a kiln as shown in the drawings, that is, the bricks 3 comprising the kiln are laid up so as to form the benches a and the arches 5, these arches extending from one head to the other. The usual scoving 6 is built around the sides of the kiln. An ashpit 7 is formed under each arch at each end thereof, and a grate 8 of suitable construction for burning coal is placed over each ash-pit, said grates )referably being on the same level as the oors of the arches, as clearly seen in the drawings. Suitable doors 9 are provided for closing the openings leading to the arches. Provision is made for creating a forced draft in the arches, and this may be done by connecting each of the ash-pits with an air conduit 10 which leads to a blower 11 so that when the blower is in operation, air will be forced into the ashpits and up through the grates.

In carrying out my process, I burn coal on the grates and wood in the center of the arches, and I find that best results can be obtained by using anthracite coal during the clearing of the kiln and bituminous coal I during the settling of the kiln, although it is within the scope of my invention to use either kind of coal. I find that during the clearing process it is desirable to burn the coal under a forced draft because when the bricks are green it is somewhat diflicult to secure a proper draft up through the kiln. I also find that during this clearing process, it is of advantage to fire the arches from both ends simultaneously. After the kiln is cleared, however, and the bricks are dry and have begun to shrink, the tendency is for the draft to establish itself up through the center of the kiln and if the burning of the coal is continued under the forced draft and the firing is done at both ends of the arches, the air current up through the kiln will converge from the heads toward the center and thus the heat generated in the arches will be conveyed toward the center of the kiln, rather than toward the heads. The result will be that while the bricks in the center of the kiln are properly burned, those in the heads are not heated enough to complete the burning and a soft brick at this point is the result. I have found that if after the kiln is cleared the coal is burned under a materially reduced draft, or possibly under a natural draft, and at the same time the arches are fired from opposite ends alternately, it is possible to throw the heat from one head to the other and to secure an even burning of the brick throughout the kiln. Accordingly in carrying out my process, I clear the kiln by burning the coal at the ends of the arches under forced draft and the wood in the center of the arches, and after the kiln is cleared, I make a comparatively heavy bed of coals in the arches at one end, as shown at the right in Fig. 1, and

then seal up the arches at these ends, and for a stated period of time, say siX hours, I fire the arches from the other end using a smaller fire at said latter end, and at the same time T materially reduce, if not on tirely eliminate, the forced draft, so that coal will be burning under an approximately natural draft. After the stated period is over, a comparatively heavy bed of coals is placed in the opposite end of the arches or at the left-hand side in Fig. 1, and the arches are scaled up at this end, and then the arches are fired from the other or right-hand end, using a lighter fire at this end. 1 find that when the forced draft is materially cut down and the firing is done as shown in Fig. 1, the heat will be thrown over into the right-hand head and all the bricks in this head will receive as much heat as those in the center of the kiln. When the six-hour period is completed and the firing is done from the right-hand end of the arches, the heat will be thrown over into the left-hand end, thus giving those bricks the benefit of suliicient heat to burn them. By thus firing at the opposite ends alternately and by using coal and wood with the reduced draft, it is possible to so distribute the heat throughout the kiln that all the bricks therein are perfectly burned and the top of the kiln will settle evenly.

The kiln herein illustrated is provided with fiues 15 which extend upwardly into the body of the brick from the crowns of the arches, and the heads are provided with chimneys 16 which extend down into the body of brick from the top of the kiln. The flues 15 serve to readily conduct the heat upwardly from the arches into the body of the brick and the chimneys may be used to build supplemental fires in during the settling process so as to assist in heating up the heads of the kiln. These chimneys are formed in the bricks when the kiln is being built and during the settling process coal is deposited in them for the purpose of building supplemental fires. These chimneys may be all of the same depth or may be of different depths, as shown in the drawings.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is 1. The method of burning brick which consists in clearing the kiln by burning coal at the ends of the arches and wood in the center of the arches and in introducing air under pressure under the bed of burning coal at each end of each arch while allowing the wood to burn without the introduction of air underneath it until the kiln is cleared and the water smoke is driven off, and then materially reducing the pressure of the air which isintroduced under the burning coal,

and maintaining such reduced pressure until the kiln is settled.

2. The steps in the method of burning brick with coal at the ends of the arches and wood in the center of the arches which consists in using a forced draft during the clearing process and then materially reducing the forced draft during the settling process.

3. The method of burning brick which consists in burning coal at the ends of the arches and wood in the center of the arches and in introducing air under pressure under the burning coal while allowing the wood to burn without the introduction of air until the kiln is cleared and the water smoke is driven off, and then firing the arches at each end alternately for a stated period of time and introducing air under the burning coal at a materially-reduced pressure from that used in clearing the kiln, and maintaining such reduced pressure until the kiln is settled.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing Witnesses.

JOSIAH Q. BENNETT.

Witnesses:

Bnssrn G. Morris, J. L. CHANDLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

